Earth moving, construction and mining equipment and the like are often used in rough, off-road terrain. These machines often employ an endless drive with track shoes that is better able to propel the machines in such environments over obstacles and uneven terrain, etc. The track chains, which include shoes, are held together by a series of interconnected track links, pins and bushings that are supported on the drive sprocket, idler and support rollers of the machine. As can be imagined, a device is typically provided that allows the track chain to be routed about the drive sprocket, idler and support rollers before the free ends of the chain are joined together. This device is called a “master link”.
Also, depending on the weight of the machine, the size of the chain, the environment in which the machine operates, and other factors, the chains and/or track shoes may wear or be damaged and may require periodic inspection, servicing, repair, and/or replacement. Hence, a master link may also be provided in the chain to allow disassembly of the chain (i.e., separation of two ends of the chain).
As can be imagined, it is desirable for master track links to have at least three traits. First, it is desirable that the master track links be reliable or durable. That is to say, the master track link should not be prone to unintentional disassembly when a track chain is in use. If this happens, the track chain assembly may fall off the undercarriage of the machine, leading to unwanted downtime and maintenance of the machine to get the machine up and running again. Second, it is desirable that the master track link be able to be easily serviceable. That is to say, it should not be time consuming to detach the master track link so that maintenance as described above can be performed. Third, it is desirable to be able to cost effectively manufacture the master track link.
Some master track link designs in current applications experience problems with the teeth such that the teeth of one master track link do not durably mate with the teeth of the mating master track link. Thus, the master track links may become separated over time, leading to a problem with the track chain falling off the undercarriage of the machine, necessitating that the machine be serviced. This may lead to unwanted downtime for the machine and an associated economic loss for the business endeavor using the machine (e.g. mining, construction, earth moving, agriculture, etc.)
Accordingly, a need exists for a method and apparatus related to a master track link that can provide a better combination of serviceability, durability or reliability and cost.
One prior master track link using five teeth that mates with five teeth of a similarly configured master track link is disclosed in U.S. Pat. No. 8,671,539 to Cho. FIG. 1 of Cho shows that the five teeth of one master track link mate closely with five teeth of another master track link. More specifically, it discloses that the front inclined surfaces of each of the five teeth mate or contact the corresponding front inclined surfaces of the five teeth of the other master track link when the pair of master track links are loaded in tension in use to complete a complete track chain.
At the same time, the top surface of the teeth and back inclined surface of the teeth do not contact the corresponding features of the teeth of the other master track link. That is to say, gaps are formed between the top surface of a tooth on one master track link and the valley located between adjacent teeth on the other master track link as well as between the rear inclined surfaces of the teeth of both master track links. As alluded to earlier, this design has not been as durable as desired. Over time, the teeth do not always remain engaged, resulting in the track chain falling off the undercarriage of the machine. Therefore, a master track link that is more durable or reliable, and that can be retrofitted with track chain assemblies already in the field is still warranted.